1. Field of the Invention
The present invention relates to a linear motor producing linear movement, and more particularly to a linear motor coil assembly having armature coils, arranged in the direction of the linear movement, and a device for cooling the armature coils.
2. Description of Related Art
In the field of a machine tool or a semiconductor manufacturing device, a linear motor for high-precision positioning of a precision table already exists. The linear motor requires a large thrust, and, in most cases, is enclosed by a cover capable of preventing intrusion of dust. Therefore, effective cooling of the linear motor becomes important.
In an existing linear motor, a cooling tube enabling refrigerant to run through is close to or in contact with armature coils which are a heat source. Patent document 1 discloses a linear motor having two lines of coils and four flat cooling tubes. The flat cooling tubes are in contact with two of the four sides of each coil. Patent document 2 discloses a linear motor having one flat cooling tube extending around two lines of coils. The flat cooling tube is in contact with two of the four sides of each coil.
Patent document 3 discloses a linear motor coil assembly including a flat cooling tube winding in one line of coils. An iron core formed with coils is affixed to a base plate. The flat cooling tube has a width larger than or equal to the axial length of the coil. Most part of the surface of each coil is in contact with the flat cooling tube.